Study shows geothermal potential

The United States is bubbling with geothermal resources,
a new study shows, and Nevada may reap the benefits.

The study, the first by the U.S. Geological Survey
in 30 years, shows policymakers the potential for
geothermal power, a trade association leader said.

"(The study) just reassures policymakers that there's
a lot of (geothermal) resources out there," said Karl
Gawell, executive director of the Geothermal Energy
Association.

The study is particularly important to the Silver
State because Northern Nevada has large fields of
geothermal resources that could be used to make electricity
for Southern Nevada. Geothermal power plants use hot
underground water and steam to generate electricity,
making them a renewable, virtually pollution-free
source of electricity.

The cost of geothermal power also is close to the
cost of power from natural gas-fired plants. Like
gas- and coal-fired plants, geothermal generation
plants run around the clock. Unlike solar and wind
power plants, geothermal provides a reliable, continual
supply of electricity without interruption.

Sierra Pacific Resources, the holding company for
electric utility NV Energy, and independent LS Power
are competing with proposals to build the first transmission
line linking Southern Nevada to the geothermal power
resources in the North.

The transmission line would serve other purposes
as well, but it is key to developing geothermal power
for use in the state because Northern Nevada already
has all the power generation capacity it needs, analysts
say.

"If we don't get that resource for ourselves, California
is going to come in and get it," Sierra Chief Executive
Officer Michael Yackira said.

The recently released Geological Survey concluded
that conventional geothermal resources are more limited
nationally than originally estimated 30 years ago.
But the federal agency also reported additional, huge
quantities of geothermal power that can be tapped
with new geothermal technology.

The Geological Survey estimated the United States
has 9,057 megawatts of electric power from conventional
geothermal systems or reservoirs with water. That
represents 260 percent more than the installed geothermal
total of 2,500 megawatts.

In the prior assessment, the federal agency estimated
20,000 megawatts of geothermal electric power, but
many of the systems then were thought to be much bigger
than they are, said Colin Williams, the geophysicist
and project chief for the geothermal study.

Government scientists estimated 517,800 megawatts
of power-generation potential in the United States
from enhanced geothermal systems in areas that lack
natural underground water supplies. That represents
half the nation's total energy consumption.

Enhanced geothermal energy wasn't assessed 30 years
ago because the technology was new.

To use enhanced geothermal resources, power developers
fracture the underground rock and pump water into
underground fissures. Nearby geothermal wells tap
the hot water or steam and generate power, Williams
said.

The areas with the best enhanced geothermal resources
are near conventional geothermal systems that have
underground water supplies, Williams said. Most of
these areas are in the Western states, including Nevada,
California and Oregon.

Gawell wants the Geological Survey to conduct more
extensive geothermal assessments with new field studies
that help identify potential geothermal areas.

The trade group official also advocates agency assessments
of low-temperature geothermal energy for direct heating
in buildings and geothermal sources for power generation
on the premises of power consumers.

The agency should expand on a study that shows geothermal
power could be drawn from oil and gas wells, Gawell
said.